Abstract
Phototropins (phot1 and phot2) are blue-light receptor kinases and mediate stomatal opening via activation of the plasma membrane H+-ATPase in guard cells. It has been demonstrated that blue light activates the guard-cell H+-ATPase through phosphorylation of a penultimate Thr and subsequent binding of the 14-3-3 protein to the phosphorylated C-terminus of H+-ATPase. So far, detection of the guard-cell H+-ATPase was performed by biochemical method using guard cell protoplasts (GCPs). However, the preparation of GCPs from Arabidopsis for this purpose needs over 10 g of rosette leaves and takes over 8 hrs. In the present study, we have established immunohistochemical method for detection of the guard-cell H+-ATPase in Arabidopsis using specific antibodies. The results showed that the H+-ATPase was mainly detected in guard cells and slightly in epidermal cells when we used the epidermal tissue from rosette leaves, and that the signals were found in peripheral of the cells. We are trying to establish whole-mount detection using rosette leaves at the present time and will report these results.